"So, what are we doing now?"

Forfeiting his plan to catch some much-needed sleep, John got up early and was dragged to St. Bart's lab by none other than Mr. Sherlock Holmes.

After the duo entered the door, John pulled up a chair and rested his chin with arm folded under him like a good student.

Sherlock has shown no sign of revealing the result of his work as he took off his jacket and fished a woman's lipstick out of the chest pocket.

The detective-chemist took off the cap, and began carefully scrutinizing the rose-colored paste inside.

"So. Finally you've decided." John wasn't going to miss a rare chance to tease Sherlock.

"What?" Sadly the potential laughingstock didn't understand the joke.

"Um….nevermind." John cleared his throat, "So this is the clue to the death of the master and the maid?"

"Obviously."

Sherlock skillfully chipped of a slice of paste and added a few drops of chemical solution to it.

After making sure John has taken out his trusty pen and notebook with his rear vision, the consulting detective began:

"I thought something was amiss the first I saw the maid's body. She didn't apply cosmetics to any part of her face save the lips. That's very unusual."

"Maybe she only liked the lipstick."

"No. Look at this brand, expensive French novelty, not something a maid can afford, I should think."

"You mean…someone had poisoned the lipstick and gave it to the maid to use?"

"I checked the maid's room, two over-sized bracelets and three outsized but expensive blouses too ill-suited to her body type or social status… also, this lipstick."

"The mistress of the house. She's quite big…she killed the maid!"

"No, she gave the lipstick to the maid, didn't think it would kill her."

"I don't understand" John licked his lips with a puzzled expression written all over his face, "then…how did the man of the house die? He couldn't possibly have used this lipstick."

"On some level…yes he did."

"Come on, Sherlock…"

"Hmph." Sherlock stared up at John with twinkling eyes, "think!"

"You…they…he's cheating on the mistress with the maid?"

"Thank god John, for using your brain for the first time," quipped Sherlock, "he kissed her, thus ingesting the poison directly."

"…So the mistress found out about them, killing two birds with one stone."

"NO, no, no, no, John!" Sherlock gave an exasperating sigh, "LOOK at that woman! She wasted more tears on the maid than the husband. Not how a killer would've behaved. That lipstick was only meant to be a gift."

"Then someone must've intended to kill the lady by offering her the lipstick, but didn't know she would give it away so quickly, indirectly killing the husband too."

"Yes."

"Then we should tell Lestrade," John pulled out his phone as he spoke, "to inquire who sent the lipstick."

…

"Already dead."

"What?"

"The killer, he's already dead."

John was stunned, "Wher…where?"

"Her husband, that woman's husband." Sherlock judged John's perplexed expression with a smirk and spoke so quick as if firing bullets out of his mouth: "Take a look at his watch, exactly an hour late, which means he has been in the central European time zone, Paris, to be precise. He just came back and didn't get a chance to reset the watch. This lipstick he brought back, Christian Dior, famous French Brand, recently released, must be a gift to his wife. Oh, think about it. It can't possibly be for the maid because she wouldn't have dared to use it in front her mistress. Now, remember their house, the pictures hanging on the wall all belonged to the lady, and the only thing missing is the wedding photo. What does that mean? It means the marriage isn't a happy one. Her stupid husband gave her a gift that fits neither her clothes nor her other accessories, rather than throwing it away, she passed it onto the poor maid. Who knew something so harmless would turn out to be a homicidal weapon. Beyond that there really isn't much to be said but to marvel at the stupidity of the man. Case solved."

…

"Ah…" John sighed after jotting it all down, "the sad truth about marriage."

"Of course."

"…"

"What?"

"I was thinking," John raised an eyebrow, "if my future wife wants to wipe me off the face of the earth, what should I do to prevent it."

Sherlock let out a simper: "I'll make sure she gets what she deserves."

"But I'll still be dead!"

"So you needed me to protect you then," Sherlock said with a hesitant undertone. "Do you remember Laura?"

"Sure….But we lost touch."

"Of course, I asked Sabastian to freeze her bank account before she withdrew all your savings."

"What the…"

"And the few hundred dollars she stole from your wallet while you were on that date, I also got it back."

"Where? I didn't see them."

"Here." Sherlock poked John's belly with his fingertip, "Why did you think I'd treat you to that lobster dish?"